Cut the long story short, I'm 25 year old male and way too underweight for my age. I have fast metabolism. I don't feel hungry alot. I stand for 8 hours at work. I spend the rest of my day at home sitting down. I eat 1 slice of bread for breakfast and glass of water as I don't feel hungry in morning. My lunch consists of fast food, ideally chicken burger meal. My dinner with family consists of Indian meal, curry or rice as I hate vegetables. I masturbate every night before sleep and sleep hungry.

I know the way I put it may sound like a troll post but nope, this is actually me and I'm wanting to change for better. Any advice is welcome. Did think about supplements but keep hearing it's waste of money.

How about trying to actually eat healthier and have food with higher calories? You could also think of getting a gym membership, and drink protein shakes, so that you can get extra calories - that will hopefully result in weight gain. Or actually, seek your GP for more 'accurate' advice.

just keep eating even if you don't feel hungry, even if you're not hungry it doesn't mean your stomach is closed off, it just means your brain hasn't signalled your stomach to get ready for digestion and blablabla you can still eat. You'll find your eating habits change as your body will adapt to it with your increased calorie intake. I work 40 hours a week walking around and stocking shelves and have extremely fast metabolism so I know the struggle.

I eat 2 bowls of cereal for breakfast and 2 servings of lunch/dinner, I also mix up a weight gainer shake whenever I feel I need the extra calories. I got this big 500g bag of almonds i just slowly munch whenever I feel as well as a full 1.5l evian bottle a day more or less.

All this and my weight is going up, very slowly but still up. Just make it simple: your goal is to gain weight, so get more food in your stomach, and block out complications like "oh no I don't feel like eating this maybe later", "meh not hungry", "hmm should I or should I not", anything else that gets in the way.